hernandez. passenger scott green watched it happen. >> he had the gun down like this, so he saw him on the ground and he shot twice. >> reporter: billy bay spotted the gunman as he made his way to the gates. >> i thought he was a random passenger, very calm, stoic faced, got closer and turned a bit and saw the assault rifle strapped on his shoulder and that's when i high tailed it and ran. >> so you were surprised -- >> that he made it all the way to the gate. >> that no one stopped. >> that he wasn't stopped by then, yeah. >> reporter: l.a.x. police chief patrick gannon says he moved armed officers from behind the checkpoint to a more visible low indication in front. >> are they going to be in the exact same moment exactly when i would hoped they would be? no, it didn't happen in this case. >> reporter: officers did swarm the airport after the shooting, but witnesses wonder why they weren't there to begin with. >> i didn't make sense to me. i thought that guy had a gun and no one was this to st